• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2000.11a
• /
• pp.527-532
• /
• 2000

The armor composite material targets such as aramid FRMLs with different type and ply number of face material and different type of back-up material, were studied to determine ballistic impact resistance and dynamic failure behavior during ballistic impact. Ballistic impact resistance is determined by $\textrm{V}_{50}$ ballistic limit, a statical velocity with 50% probability for complete penetration, test method. Also dynamic failure behaviors are respectfully observed that result from $\textrm{V}_{50}$ tests. $\textrm{V}_{50}$ tests with $0^{\circ}$ obliquity at room temperature were conducted with projectiles that were able to achieve near or complete penetration during high velocity impact tests. As a result, ballistic impact resistance of anodized Al 5052-H34 alloy(2 ply) is better than that of anodized Al 5052-H34 alloy(1 ply), but Titanium alloy showed the similar ballistic impact resistance. In the face material, ballistic impact resistance of titanium alloy is better than that of anodized Al 5052-H34 alloy. In the back-up material, ballistic impact resistance of T750 type aramid fiber is better than that of CT709 type aramid fiber.

• Journal of the Korean Society for Precision Engineering
• /
• v.27 no.2
• /
• pp.94-101
• /
• 2010

Composite materials have a higher specific strength and modulus than traditional metallic materials. Additionally, these materials offer new design flexibilities, corrosion and wear resistance, low thermal conductivity and increased fatigue life. These, however, are susceptible to impact damage due to their lack of through-thickness reinforcement and it causes large drops in the load-carrying capacity of a structure. Therefore, the impact damage behavior and subsequently load-carrying capacity of impacted composite materials deserve careful investigation. In this study, the residual strength and impact characteristics of plain-woven CFRP composites with impact damage are investigated under axial tensile test. Impact test was performed using drop weight impact tester. And residual strength behavior by impact was evaluated using the caprino model. Also we evaluated behavior of residual strength by change of mass and size of impactor. Examined change of residual strength by impact energy change through this research and consider impactor diameter in caprino model.

• Proceedings of the KSME Conference
• /
• 2004.04a
• /
• pp.330-335
• /
• 2004

The needs of walking assistive device such as the Ankle Foot Orthosis (A.F.O.) are getting greater than before. However, most of the A.F.O. are generally imported rather than domestic manufacturing. The major reason of high import reliability is the rack of impact properties of domestic commercial products. Therefore, this research is going to focus on the evaluation of impact properties of the A.F.O. which has the high import reliability. Unfortunately, these kinds of researches are not performed sufficiently. This research is going to evaluate impact energy behavior in composite materials such as the glass/epoxy (S-glass, $[0/90]_{2S}$) and the aramid/epoxy (Kevlar-29, woven type, 8 ply) of ankle foot orthosis. The approach methods were as follows. 1) The history of impact load and impact energy due to the various velocities. 2) Relationship between the deflection and damage shape according to the impact velocities. 3) The behavior of absorbed energy and residual strength rate due to the various impact velocities.

• Composites Research
• /
• v.22 no.6
• /
• pp.18-22
• /
• 2009

In this paper, we examined impact force and impact behavior through low velocity impact tests of composite laminates. And through c-scan as nondestructive inspection, explored the damaged area being difficult to examine with the visual inspection. Through CAI tests, we also measured the compression strength of composite laminates subjected to low velocity impact. To examine the characteristics of impact behavior measured from low velocity impact test, nondestructive inspection, and CAI test, the simulated data are generated from the test data using Monte-Carlo simulation, then represented it by probability distribution. The testing results using visible stochastic distribution were examined and compared.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2000.04a
• /
• pp.20-25
• /
• 2000

In order to study the impact fracture behavior of brittle materials, a steel-ball-impact experiment was Performed. Five kinds of materials were used in this study : soda-lime glass plates, glass/epoxy prepreg-one layer-bonded and unbonded glass plates, glass/epoxy prepreg-three layers-bonded and unbonded glass plates. Fracture patterns, the maximum stress and absorbed fracture energy were observed according to various impact velocities 40-120m/s. With increasing impact velocity, ring crack, cone crack, radial crack and lateral crack took place in the interior of glass plates. The generation of such cracks was largely reduced with glass/epoxy prepreg coating. Consequently, it is thought that the characteristics of the dynamic Impact fracture behavior could be evaluated using the absorbed fracture energy and the maximum stress measured at the back surface of glass plates.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2002.05a
• /
• pp.353-356
• /
• 2002

In vehicle accidents, the rolling, pitching, and yawing which are produced by collisions affect the motions of vehicle. Therefore, vehicle behavior under impact situation should be analyzed in three-dimension. In this study, three-dimensional vehicle dynamic equations based on impulse-momentum conservation principles under vehicle impact are introduced for simulation. This analysis has been performed by the real vehicle impact data from JARI and RICSAC. This study suggested each system modeling such as suspension, steering, brake and tire as well as the appropriate vehicle behavior simulation model with respect to pre and post impact.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2002.10a
• /
• pp.262-267
• /
• 2002

Impact behavior of polycarbonate in various defect state was investigated using an instrumented impact fester. A mettled of analyzing raw impact data was developed and successfully demonstrated the impact behavior in terms of load-displacement and energy-displacement curves. This technique was shown to be capable of separating defect, no-defect initiated fractures as well as their propagation behaviors.

• The Journal of Asian Finance, Economics and Business
• /
• v.7 no.2
• /
• pp.169-180
• /
• 2020

Globalization has led to a dramatic increase in intercultural service encounters between services providers and customers from diverse cultural backgrounds. This paper explores the causal relationship between service employees‟ cultural intelligence and adaptive sales behavior in intercultural service encounters, and the mediating effect of cognitive and emotional empathy on this relationship. A quantitative survey methodology was utilized to collect data on 341 salespeople at duty-free shops located on Jeju Island, Korea. Data analysis was conducted using SPSS 18 and Amos 18. The results show that cultural intelligence has a significant impact on cognitive empathy, emotional empathy, and adaptive sales behavior. Cognitive empathy has a positive impact on adaptive sales behavior, whereas the relationship between emotional empathy and adaptive sales behavior is not significant. Additionally, cognitive empathy mediates the relationship of cultural intelligence and adaptive sales behavior. This study has useful managerial implications for employee selection, training, and development in service firms engaged in intercultural service encounters. This study extends prior research on intercultural service encounters by exploring the direct impact of cultural intelligence on intercultural adaptation and the mediating effect of empathy, suggesting the presence of a cognitive mechanism that plays a key role in the impact of cultural intelligence on adaptive sales behavior.

• International Journal of Safety
• /
• v.4 no.2
• /
• pp.6-11
• /
• 2005

The goals of the paper are to understand the impact damage behavior and identify the effect of surface protective materials on impact resistance in filament wound composite pressure vessels. For these, a series of low velocity impact tests was performed on specimens cutting from the full scale pressure vessel by the instrumented impact testing machine. The specimens are classified into two types, which are with and without surface protective material. The visualization for impact damage by two different impactors is made by metallurgical microscope. Based on the impact force history and damage, the impact resistance parameters were employed,rod its validity in identifying the damage resistance of filament wound composite pressure vessel was reviewed. As the results, the impact resistance of the filament wound composites and its dependency on the surface protective material were evaluated quantitatively

• Journal of Industrial Convergence
• /
• v.5 no.2
• /
• pp.77-97
• /
• 2007

The 420 employees as subject for emprical analysis were selected in Banwol & Sihwa Industrial Complex in Ansan area. This study shows the followings; 1. In the group where the task is unstructured and the subordinate's ability is high, the achievement - oriented and participative leader behavior have positive impact on the subordinate's expectancy. 2. In the group where the task is unstructured and the subordinate's ability is low, the directive leader behavior has no significant impact on the subordinate's expectancy. 3. In the group where the task is structured and the subordinate's ability is high, the supportive leader behavior has positive impact on the subordinate's expectancy. 4. In the group where the task is structured and the subordinate's ability is low, only supportive leader behavior has positive impact on the subordinate's expectancy, and the directive leader behavior has on significant impact. Finally this study indicates the implication for future theoretical and empirical delelopment.